21772018 has 16 divisors (see below), whose sum is σ = 33555456. Its totient is φ = 10589040.

The previous prime is 21772001. The next prime is 21772033. The reversal of 21772018 is 81027712.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32608 + ... + 33268.

It is an arithmetic number, because the mean of its divisors is an integer number (2097216).

Almost surely, 2^21772018 is an apocalyptic number.

21772018 is a deficient number, since it is larger than the sum of its proper divisors (11783438).

21772018 is a wasteful number, since it uses less digits than its factorization.

21772018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1089.

The product of its (nonzero) digits is 1568, while the sum is 28.

The square root of 21772018 is about 4666.0495068098. The cubic root of 21772018 is about 279.2326694858.

The spelling of 21772018 in words is "twenty-one million, seven hundred seventy-two thousand, eighteen".